Combined multipole magnet and dipole scanning magnet

Abstract

A combined scanning and focusing magnet for an ion implantation system is provided. The combined scanning and focusing magnet has a yoke having a high magnetic permeability. The yoke defines a hole configured to pass an ion beam therethrough. One or more scanner coils operably are coupled to the yoke and configured to generate a time-varying predominantly dipole magnetic field when electrically coupled to a power supply. One or more focusing coils are operably coupled to the yoke and configured to generate a predominantly multipole magnetic field, wherein the predominantly multipole magnetic field is one of static or time-varying.

What is claimed is: 
     
       1. A combined scanning and focusing magnet, comprising:
 a yoke having a high magnetic permeability, the yoke defining a hole configured to pass an ion beam therethrough; 
 one or more scanner coils operably coupled to the yoke and configured to generate a time-varying predominantly dipole magnetic field when electrically coupled to a power supply; 
 one or more focusing coils operably coupled to the yoke and configured to generate a predominantly multipole magnetic field, wherein the predominantly multipole magnetic field is one of static or time-varying, wherein leads of the focusing magnet coil leads are positioned to eliminate a mutual inductance between the focusing magnet and the scanning magnet; and 
 an adjustable auxiliary yoke, wherein one or more auxiliary coils are wrapped around the auxiliary yoke, wherein the one or more auxiliary coils are positioned in a fringe field region associated with the one or more scanner coils, whereby a mutual inductance between the one or more focusing coils and the one or more scanning coils is generally eliminated. 
 
     
     
       2. The combined scanning and focusing magnet of  claim 1 , wherein the yoke comprises a generally rectangular steel yoke. 
     
     
       3. The combined scanning and focusing magnet of  claim 1 , wherein the yoke comprises a plurality of laminated ferrous sheets. 
     
     
       4. The combined scanning and focusing magnet of  claim 1 , further comprising an alternating current power source, wherein the one or more scanner coils and one or more focusing coils are configured to receive power from the alternating current power source. 
     
     
       5. The combined scanning and focusing magnet of  claim 1 , further comprising a direct current power source, wherein the one or more scanner coils and one or more focusing coils are configured to receive power from the direct current power source. 
     
     
       6. The combined scanning and focusing magnet of  claim 1 , wherein the one or more focusing coils comprise Panofsky-type multipole coils. 
     
     
       7. The combined scanning and focusing magnet of  claim 1 , wherein the one or more focusing coils comprise one or more bedstead coils. 
     
     
       8. The combined scanning and focusing magnet of  claim 1 , wherein the one or more scanner coils comprise one or more bedstead coils. 
     
     
       9. An ion implantation system, comprising:
 an ion source configured to generate an ion beam; 
 a mass resolving magnet configured to mass resolve the ion beam; 
 a mass resolving aperture positioned downstream of the mass resolving magnet, wherein the mass resolving aperture is configured to filter undesirable species from the ion beam, and wherein the ion beam generally diverges after passing through the mass resolving aperture; and 
 a combined scanning and focusing magnet positioned downstream of the mass resolving magnet, wherein a path of the ion beam is electromagnetically scanned, while concurrently focusing the ion beam, wherein the combined scanning and focusing magnet, comprises:
 a yoke having a high magnetic permeability, the yoke defining a hole configured to pass an ion beam therethrough; 
 one or more scanner coils operably coupled to the yoke and configured to generate a time-varying predominantly dipole magnetic field when electrically coupled to a power supply; 
 one or more focusing coils operably coupled to the yoke and configured to generate a predominantly multipole magnetic field, wherein the predominantly multipole magnetic field is one of static or time-varying, wherein leads of the focusing magnet coil leads are positioned to eliminate a mutual inductance between the focusing magnet and the scanning magnet; and 
 an adjustable auxiliary yoke, wherein one or more auxiliary coils are wrapped around the auxiliary yoke, wherein the one or more auxiliary coils are positioned in a fringe field region associated with the one or more scanner coils, whereby a mutual inductance between the one or more focusing coils and the one or more scanning coils is generally eliminated. 
 
 
     
     
       10. The ion implantation system of  claim 9 , wherein the yoke comprises generally rectangular steel yoke. 
     
     
       11. The ion implantation system of  claim 9 , wherein the yoke comprises plurality of laminated ferrous sheets. 
     
     
       12. The ion implantation system of  claim 9 , wherein the one or more focusing coils comprise Panofsky-type multipole coils. 
     
     
       13. The ion implantation system of  claim 9 , wherein the one or more focusing coils comprise one or more bedstead coils. 
     
     
       14. The ion implantation system of  claim 9 , wherein the one or more scanner coils comprise one or more bedstead coils. 
     
     
       15. The ion implantation system of  claim 9 , further comprising a controller operably coupled to the ion source, mass resolving magnet, and combined scanning and focusing magnet, and configured to control the operation of at least one of the ion source, mass resolving magnet, and combined scanning and focusing magnet, at least in part, on a desired dosage and distribution of ions to be implanted into the workpiece. 
     
     
       16. The ion implantation system of  claim 15 , further comprising an alternating current power source, wherein the controller is configured to selectively provide alternating current to one or more of the scanner coil and one or more focusing coils. 
     
     
       17. The ion implantation system of  claim 15 , further comprising a direct current power source, wherein the controller is configured to selectively provide direct current to one or more of the scanner coil and one or more focusing coils. 
     
     
       18. The ion implantation system of  claim 9 , further comprising a measurement component configured to determine one or more characteristics of the ion beam, wherein the controller is further operably coupled to the measurement component and configured to further control the operation of at least one of the ion source, mass resolving magnet, and combined scanning and focusing magnet based, at least in part, on the determined one or more characteristics of the ion beam.